This paper examines how risky labor income and retirement affect optimal portfolio choice. With idiosyncratic labor income risk, the optimal allocation to stocks is unambiguously larger for employed investors than for retired investors, consistent with the typical recommendations of investment advisors. Increasing idiosyncratic labor income risk raises investors' willingness to save and reduces their stock portfolio allocation towards the level of retired investors. Positive correlation between labor income and stock returns has a further negative effect and can actually reduce stockholdings below the level of retired investors.

This paper investigates options market reaction to changes in the instantaneous variance of the underlying asset. There are three main findings. First, options market investors underreact to individual daily changes in instantaneous variance. Second, these same investors overreact to periods of mostly increasing or mostly decreasing daily changes in instantaneous variance. Third, they tend to underreact (overreact) to current daily changes in instantaneous variance that are preceded mostly by daily changes of the opposite (same) sign. The third finding can reconcile the first two and is also consistent with well‐established cognitive biases.

Economic distortions can arise when financial claims trade at prices set by an intermediary rather than direct negotiation between principals. We demonstrate the problem in a specific context, the exchange of open‐end mutual fund shares. Mutual funds typically set fund share price (NAV) using an algorithm that fails to account for nonsynchronous trading in the fund's underlying securities. This results in predictable changes in NAV, which lead to exploitable trading opportunities. A modification to the pricing algorithm that corrects for nonsynchronous trading eliminates much of the predictability. However, there are many other potential sources of distortion when intermediaries set prices.

Changes in the capital gains tax rules facing individual investors do not affect the incentives for “window dressing” by institutional investors, but they can affect the incentives for year‐end tax–induced trading by individual investors. Empirical evidence for the 1963 to 1996 period suggests that when the tax law encouraged taxable investors who accrued losses early in the year to realize their losses before year‐end, the correlation between early year losses and turn‐of‐the‐year returns was weaker than when the law did not provide such an early realization incentive. These findings suggest that tax‐loss trading contributes to turn‐of‐the‐year return patterns.

Diversified conglomerates are valued less than matched portfolios of pure‐play firms. Recent studies find that this diversification discount results from conglomerates' inefficient allocation of capital expenditures across divisions. Much of this work uses Tobin's q as a proxy for investment opportunities, therefore hypothesizing that q is a good proxy. This paper treats measurement error in q . Using a measurement‐error consistent estimator on the sorts regressions in the literature, I find no evidence of inefficient allocation of investment. The results in the literature appear to be artifacts of measurement error and of the correlation between investment opportunities and liquidity.

Proprietary data allow us to distinguish between institutional investors' orders directed to soft‐dollar brokers and those directed to other types of brokers. We find that soft‐dollar brokers execute smaller orders in larger market value stocks. Allowing for differences in order characteristics, we estimate the incremental implicit cost of soft‐dollar execution at 29 (24) basis points for buyer‐ (seller‐) initiated orders. For large orders, incremental implicit costs are 41 (30) basis points for buys (sells). However, we document substantial variability in these estimates, and research services provided by soft‐dollar brokers may at least partially offset these costs.

We propose regression‐based tests for mean‐variance spanning in the case where investors face market frictions such as short sales constraints and transaction costs. We test whether U.S. investors can extend their efficient set by investing in emerging markets when accounting for such frictions. For the period after the major liberalizations in the emerging markets, we find strong evidence for diversification benefits when market frictions are excluded, but this evidence disappears when investors face short sales constraints or small transaction costs. Although simulations suggest that there is a possible small‐sample bias, this bias appears to be too small to affect our conclusions.